Put the bamboo chair in a well ventilated area that is also suited for painting, such as a garage or shed.
Sand away the old paint using a medium-fine-grit sandpaper. Make the surface just rough enough for new paint to adhere. Do not leave any of the old paint on the bamboo chair or the new paint might not stick or show spots through the new coat of paint.
Apply wood primer to get a bonding surface for the new paint to adhere to. Brush on a light coat so as not to darken the wood. Let it dry for about 3 hours before proceeding to the new paint.
Repaint the bamboo chairs with a color of your choosing, using light, even strokes. Let the first coat dry for three to four hours before applying a second coat to assess how dark the first coat appears. If the color is to your liking, skip to the next step. If too light, apply a second coat.
Brush on a coat of sealant to protect the bamboo wood and the paint finish. Brush on the sealant going with the wood grain of the bamboo as much as possible. Let it dry for a day before using the newly repainted bamboo chair.